Self-started voltage-source series-resonant converter for high power induction heating and melting applications

An inverter configuration for high power induction heating and melting applications is presented. The proposed inverter covers loads with quality factors up to 12 while featuring self-starting capabilities. This is achieved by properly distributing the compensated capacitor between the primary and the secondary of the matching transformer. The transient analysis of the configuration defines the maximum ratio of the primary and secondary capacitors in order to assure self-starting. On the other hand, the steady state analysis defines the minimum ratio to limit the operating flux level of the matching transformer to a safe level. This paper identifies the sources of self-starting failures in the standard configuration and presents the transient and steady state analyses towards a systematic procedure of components design for the proposed topology. Experimental results on a laboratory prototype to prove the theoretical considerations are also included.